Photosensitive polymers

ABSTRACT

This invention relates to a composition comprising one or more members selected from the group consisting of vinyl ether derivatives of hydroxychalcone and homologs thereof and a cationic polymerization catalyst. It further concerns a photosensitive polymer obtained by polymerizing or copolymerizing the said composition. The polymerization or copolymerization product is a linear polymer or linear copolymer wherein only the vinyl group is polymerized and the photosensitive group is retained quantatively in the side chain. This polymer or copolymer has high photosensitivity and enables a photocrosslinking reaction to occur uniformly.

United States Patent Kato et al. 1 Mar. 25, 1975 [54] PHOTOSENSITIVEPOLYMERS 3,364,282 1/1968 DAlelio 260/88.1

[75] Inventors: Masao Kato, Yokohama; Masaki I Hasegawa Tokyo; Tarolchijyo, Primary ExammerChr1stopher A. Henderson Kamakum, a" f JapanAttorney, Agent, or Firm-Ernest G. Montague; Karl F. Ross; Herbert Dubno[73] Assignee: Agency of Industrial Science &

Technology, Tokyo, Japan 57 ABSTRACT [22] Filed: June 8, 1972 l Thisinvention relates to a composition comprising [21] Appl' 272331 one ormore members selected from the group consist- R l t d U S, A li ti D ting of vinyl ether derivatives of hydroxychalcone and [63] continuationin pan of Sen Na 46 836 June 16 homologs thereof and a cationicpolymerization cata- 1970 abandonedlyst. It further concerns aphotosensitive polymer obtained by polymerizing or copolymerizing thesaid 52 U.S Cl 2 0/47 UA, 9 1 15 P 117/124 composition. Thepolymerization Of copolymerization [51] Int. Cl. C08t' 3/40 Product is alinear polymer or linear copolymer [58] Field of Search 260/47 UA, 47UR:63 R, wherein only the vinyl group is polymerized and the 260/6396/115 P photosensitive group is retained quantatively in the sidechain. This polymer or copolymer has high photo- [56] References Citedsensitivity and enables a photocrosslinking reaction to UNITED STATESPATENTS occur $934,526 4/1960 Hoffmann 260/88.1 4 Claims, No DrawingsPHOTOSENSITIVE POLYMERS REFERENCE TO RELATED APPLICATION This is acontinuation-in-part of our copending application Ser. No. 46,836 filedJune 16, 1970 now abandoned.

FIELD OF THE INVENTION This invention relates to a novel photosensitivepolymer. More particularly, this invention relates to a photosensitivepolymer in which only the vinyl group is polymerized and an unsaturatedgroup of the generic formula:

(wherein R is a member selected from the group consisting of hydrogengroups, lower alkyl and alkoxy groups and halogens, and n is an integerhaving the value 1, 2 or 3) is contained in the side chain.

BACKGROUND OF THE INVENTION The photosensitive resins of thephotodimerization type which have heretofore been known includecompositions which contain, as photosensitive components thereof,compounds of the type having cinnamic acid esterifled with polyvinylalcohols and compounds of the type having benzalacetophenone introducedinto the aromatic ring of polystyrene. In the case of photosensitiveresin compositions which are obtained by such polymer reaction, however,it is generally not possible to have the photosensitive groupsintroduced at a definite ratio into the backbone polymer chain. Thusthese resin compositions provide nonuniform photoreactions, tend toinduce such undesirable phenomena as fogging and defy all attempts toimprove the sensitivity above a certain level.

SUMMARY OF THE INVENTION The photosensitive polymer of this invention isvery simple to manufacture. It has a structure in which thecharacteristic group capable of imparting photosensitivity is completelyintroduced into the basic polymer unit.

The polymer of this invention has, as its photosensitive component, alinear cationic polymer or linear cationic copolymer consisting of oneor more compounds represented by the following generic formulas:

and an unsaturated group of Formula l) or (2) is contained as thephotosensitive group in the side chain.

The polymer or copolymer of this invention, therefore, has a structurein which the said photosensitive group is incorporated regularly andcompletely. As a result, it has higher photosensitivity thanphotosensitive polymers heretofore known to the art and permitsphotosensitizing reactions to occur uniformly.

What is more, the polymer of this invention has outstanding behaviors asa photoresist; it provides soft photographic tone, high adhesiveness andexcellent photographic resolution. It is, therefore, used for theproduction of precision printing plates, integrated circuits, largescale integrated circuits, etc.

Linear copolymers formed of the compounds of F ormula (1) and (2) withother chain polymerizable compounds are also included in the polymers ofthis invention. Proper selection of these chain polymerizable compounds,therefore, enables produced linear copolymers to acquire any desireddegree of photosensitivity ethoxychalcone,

for different purposes.

his the main object of this invention to provide a novel, industriallyuseful linear polymer or linear copolymer possessed of very highphotosensitivity.

Other objects and characteristic features of the present invention willbecome apparent to those skilled in the art from the following, moredetailed description of the invention.

Concrete examples of the compounds of Formulas (3) and (4) which are theraw materials for the polymers of this invention are 4'-(B-vinyloxy)-4-methoxy-4'-(B-vinyloxy)ethoxy-4-(B-vinyloxy)ethoxyphenylbutadienalacetophenone,4-(B-vinyloxy)ethoxychalcone, 4-(l3-vinyloxy)-3-methoxychalcone, 4-(B-vinyloxy)ethoxy-4'methylchalcone, 4-(8-vinyloxy)ethoxy-4-methoxychalcone and 4-(B-vinyloxy)ethoxyphenylbutadienalacetophenone.

These compounds are generally produced by either heating sodium,potassium, lithium and other alkali metal salts of 4-hydroxychalcone,4'-hydroxychalcone and homologs thereof together with 2-haloethylvinylethers or heating the said salts in such alcohols as methanol andethanol or in mixtures of these alcohols with chalcone,

such po lars olventsas dioxane, tetrahydrofuran etc. In

2%..Fa9tthatth2919291 2M??? 2991 29 .q ffsxia ethersalkylisoalkenylvinyl ethers, olefins, alkylstyrenes, halostyrenes,isoalkenylstyrenes, vinyl carbazole, vinyldioxolanes, dialkoxyethylenes,butadiene,

and isoprene. These polymers and copolymers are novel substances whichhave never been reported in literature. They can be polymerized in thepresence of a cationic polymerization catalyst.

As the cationic polymerization catalyst, there may be used one member ora cocatalyst made up of two or more members selected from the groupconsisting of boron trifluoride, etherification products thereof,stannic chloride, aluminum chloride, aluminum sulfate, titaniumchloride, zinc chloride, and sulfuric acid. The amount of the catalystto be used is in the range of 10 0.001 to lOpercent, preferably from0.01 to percent, by weight based on the monomer. No completepolymerization is obtained when the amount is below the lower limit ofthe said range. When the amount exceeds the upper limit of the range,however, the molecular weight of the resultant polymer fails to reachthe desired level, though the velocity of polymerization may beincreased.

The polymerization is usually carried out in a solvent. As the solvent,there may be used one member or a mixed solvent composed of two or moremembers selected from the group consisting of benzene, toluene,methylene chloride, ethylene chloride, nitromethane, carbontetrachloride, and nitrobenzene which are invariably inactive tocationic polymerization.

Generally, the monomer concentration is in the range of from 0.5 to 90percent by weight, though the practically desirable range is from 1 to70 percent by weight.

Generally, the polymerization temperature is from l30 to 100C.

The polymerization is generally carried out by following an ordinaryprocedure, with due precautions exercised not to allow water to enterthe polymerization system. On completion of the polymerization, a smallamount of ammonia, pyridine or some other weakly basic substance isintroduced into the solution so as to inactivate the catalyst. Thesolution may be preserved without further modification or it may beconcentrated and preserved in the concentrated form. Otherwise, thissolution may be poured into an alcohol or some other suitablenon-solvent containing therein a small proportion of the aforesaidweakly basic substance so as to liberate and refine the polymercontained therein.

Now, an explanation is made of the method adopted for confirming thefact that the novel compounds of this invention have a structure whereinonly the vinyl group is polymerized and the structures of Formulas (l)and (2), namely the chalcone and its homologous .sttusturerates ntam dnth S d; cha n..- W

The explanation is first made with respect to 4-(B- vinyloxy)-chalcone.

The NMR spectra of the dichloroform solution of4-(B-vinyl-oxy)ethoxychalcone show a signal due to the protons of vinylgroup at 6.50 ppm and two signals due to the protons of olefinic doublebond (trans) each at 6.92 ppm and 7.95 ppm. In the NMR spectra of theproduct obtained by the cationic polymerization of the said chalcone,the signal at 6.50 ppm has disappeared and the signals at 6.92 ppm and7.95 ppm have remained. The ratio in relative area of the latter signalsto those of phenyl group and methylene group (of the main chain)indicates that the olefinic double bond has not participated in thepolymerization. I

Completely similar results are obtained when the other members from theaforesaid group of compounds are subjected to cationic polymerization.Thus, it has been confirmed that their respective polymers invariablyretain olefinic or a conjugated double bond quantitatively in the sidechain.

Also in the case of the copolymerization of vinyl ether derivatives ofhomologs with the aforementioned cationically polymerizable monomerssuch as isobutylvinyl ether and a-methyl-styrene which are generallyknown to exhibit vinyl polymerizing property, it has been confirmed byNMR spectrum analysis that soluble copolymers retaining the structure ofchalcone or a homolog thereof quantitatively in the side chain areobtained in satisfactory yields similarly to polymers obtained in thecase of homopolymerization.

As previously mentioned, the polymers and copolymers thus formed havethe structure of chalcone and a homolog thereof represented by thegeneric formulas (l) and (2) as the side chains in the molecule. Byvirtue of the photosensitivity inherent to these peculiar structures,the polymers and copolymers are used for the production ofphotosensitive resins, varnishes and paints which enjoy excellentbehaviors;

As will become evident from the Examples presented hereinafter, thesepolymers and copolymers are obtained in very high yields and aresoluble.

When the polymers of the present invention are put to uses for whichphotosensitivity is one requirement, they may contain fillers, thermalpolymerization inhibitors and the like which are popularly used asauxiliary ingredients. As the filler, there are used such inorganicsubstances as glass powder and silica and such synthetic resins aspolypropylene, polymethacrylate', polyamide, and polyethyleneterephthalate. The thermal polymerization inhibitors which are usablefor the present invention include hydroquinone, pyrogallol, methyleneblue, phenol, and n-butyl-phenol.

When the polymer composition of this invention is exposed to thesunlight or to the rays from a xenon lamp, mercury lamp, carbon arc orsimilar light source, the aforementioned homopolymer or copolymer whichis the photosensitive ingredient undergoes a crossinkiu 29%?!11". HFl QS HWPilXl lize Because of this reaction, the composition can be used asa photosensitive resin for the production of photoresist, printing resinplate and photosetting bonding agent. It may also be used as the rawmaterial for the production of film and other molded articles.

When the film formed of the photosensitive composition of this inventionis exposed to rays through a negative film held fast against it andsubsequently treated .wi la i itable lv m suclt si s n toluene, rq-

form, carbon tetrachloride, or ethylene dicloride, the unexposed portionof the film is washed away and the exposed portion remains. Thus, thefilm produces a relief image.

The following Examples are further illustrative of this invention, andit will be understood that the invention is not limited thereto.

EXAMPLE 1 Manufacture of 4-(B-vinyloxy)ethoxychalcone 13.5cc of methanolsolution containing sodium methoxide (wherein Na is contained in anamount of 0.0763g per lcc of said sodium methoxide) was added to 30cc ofmethanol disolved in 10.0g of 4- hydroxychalcone, and methanol wasthereafter removed under reduced pressure. The resultant is well groundto fine powder, and 50g of 2-chloroethyl vinyl ether and 0.5g of methyltriethyl ammonium iodide Manufacture of polymer In a moistureproof flaskfitted with a calcium chloride tube, a solution of 1.00g of4-(B-vinyloxy)ethoxychalcone in 9.00g of methylene chloride was cooledto 25C and combined, while under agitation, with 0.020g of borontrifluride etherate. At the same temperature, agitation was continuedfor 3.5 hours. After polymerization, the contents were poured into alarge volume of methanol containing a small volume of ammonia, to obtaina light yellow polymer.

The yield was 0.76g and the reduced viscosity (0.5 g/dl) was 0.15.

Treatment of photosensitive polymer The polymer thus obtained wasdissolved in a mixture of methyl ethyl ketone with chloroform. Thesolution was formed into a film on a glass plate and exposed to thehigh-pressure mercury lamp (50 W) as light source placed at a distanceof cm. Consequently, the film was insolubilized.

EXAMPLE 2 Manufacture of 4-(B-vinyloxy)ethoxychalcone copolymer Asolution of 0.20g of 4-(B-vinyloxy)ethoxychalcone and 1.80g' of isobutylvinyl ether in 2.00g of methylene chloride was combined, while underroom temperature (15C), with 0.9mg of aluminum sulfate-sulfuric acidcomplex (Al (SO /3H SO /7H O). Agitation was continued for 3.5 hours.After polymerization, the content was subjected to the same treatment asused in Example l, to yield a light yellowish brown polymer.

The yield was 1.73g and the reduced viscosity was 0.55.

. 65 Treatment of photosensitive copolymer The polymer thus obtained wasformed into a film and exposed to the mercury lamp for 10 minutesaccording to the same method as used in Example 1. Consequently, thefilm was insolubilized.

EXAMPLE 3 Manufacture of 4-(,8-vinyloxy)ethoxychalcone 13.5cc ofmethanol solution containing sodium methoxide (wherein Na is containedin an amount of 0.0763g per lcc of said sodium methoxide) was added to30cc of methanol disolved in 10.0g of 4- hydroxychalcone, and methanolwas thereafter removed under reduced pressure. The resultant product iswell ground to fine powder, and 50g of Z-chloroethyl vinyl ether and0.5g of methyl triethyl ammonium iodide were added thereto. The mixturewas refluxed under agitation for 2 hours. The resulting solution wassucked and filtered, and sodium chloride thus produced was separated.2-chloroethyl vinyl ether remaining in the filtered solution was removedby distillation. The remainder, after dissolved with chloroform, wastwice washed with water and dried by adding sodium sulfate anhydride.Further, the solvent was removed and crystals of4'-(B-vinyloxy)ethoxychalcone was obtained as a yield of 12.08g. Thecrystals of 4-(B-vinyloxy)ethoxychalcone were recrystalled withn-hexane-benzene mixture and refined.

Melting point: 87-88C.

Results of elementary analysis:

Calculated (C H O C, 77.53%; H, 6.16%.

Found: C, 77.50%; H, 6.15%.

Manufacture of 4-(B-vinyloxy)ethoxychalcone polymer A solution of l.00gof 4'-(B-vinyloxy)ethoxychalcone in 9.00g of methylene chloride wascooled to 37C and combined with 0.02g of boron trifluoride etherate. Atthe same temperature, agitation was continued for 3 hours. Afterpolymerization, the contents were subjected to the same after-treatmentas used in Example 1 to yield a light yellow polymer.

The yield was 0.82g and the reduced viscosity was 0.23.

Treatment of photosensitive polymer According to the same method as usedin Example 1, the polymer thus obtained was formed into a film andexposed to light. Consequently, the film was insolubilized.

EXAMPLE 4 Manufacture of '4'-( Bvinyloxy)ethoxychalcone copolymer)Treatment of photosensitive polymer The polymer thus obtainedwasformedinto a film sequently, the film was insolubilized.

3 ,8 7 3 ,500 v 7 a and exposed to light in the manner of Example 1.Con- EXAMPLE 8 Manufacture of 4-(B-vinyloxy)ethoxyphenylbutadienalacetophenone EXAMPLE h h l I 5 Amixture of 1.00g of 4'-(/3-vinyloxy)et oxyp eny Treatment of 4(B-T3110)ethoxychalcone butadienalacetophenone in 9.00g of methylenechlocopqymer ride was cooled to -25C and combined with 0.03g of i borontrifluoride etherate. At the same temperature, t g3 9 223533 gf z ggggfig g zg g pgggi: 'agitation was continued for 3 hours. Afterpolymeriza- 10 tion, the reaction system was treated in the samemanylene chloride was combined with 2mg of aluminum Her as in Exam 1e 1to roduce a 0| met sulfate'sulfuric acid complex and continuouslyagitated The ield g 0 i the z g vis'cosit was at l5-l6C for 20 hours.After polymerization, the D is y W H 7 content was subjected to the sametreatment as used in i Example 1, to afford a light yellowish brownpolymer. T t t f h t iti polymer The yield was 4.13g and the reducedviscosity was The polymer thus Obtained was formed into a film V andexposed to light in the manner of Example 1. The

film w s co 5 ue tl i l b'l' d. Treatment of photosensitive polymer i is1 53 g u A film formed of the resultant polymer was exposed 1, Aphotosensitive polymer consisting f a l to light in the manner ofExample 2. Consequ y, ized vinyl chain of repetitive units selected fromthe film was insolubilized. group consisting of -o-cr-1 -crr oi lg, m aand EXAMPLE 6 wherein R is hydrogen, halogen, lower alkyl or lowerManufacture of alkoxy, and n is l, 2 or 3.4-(B-vinyloxy)ethoxy-3-methoxychalcone polymer The P of Clam wi pp y fhas at least two different repetitive units which differ in A lu 0f 8 offi" at least one of R and n.

methoxychalcgne in 3 of methylene- Chloride a 3. A photosensitivecopolymer having'a chain formed cooled to ---30 C and combined with 0.01g of boron tr1- by copolymerizing the CHFCH group of at least one uq isqthq ateiyr bean empstemttl 15E599 monomer (1) of the formula wascontinued for 3 hours. After polymerization, the wherein R is hydrogen,halogen, lower alkyl or lower reaction mixture was treated in the mannerof Example alkoxy, and n is l, 2 or 3, with a chain cationically co- 1,to afford a polymer. polymerizable unsaturated monomer (2), to form aco- The yield was 0.85g and the reduced viscosity was 5 polymer chaincontaining pendant repetitive photosen- 0.09. sitive units (3) selectedfrom the formulae EXAMPLE 7 Manufacture of -O-CH -Cl-l .0 'Q-GO- (CH=CH)-R and 4-(B-vinyloxy)ethoxy-4-methylchalcone polymer A mixture of 1.50gof 4-(B-vinyloxy)ethoxy-4- Z Z" Q H) O-G41 methylchalcone in l4.00g ofmethylene chloride was cooled to 30C and combined with 0.04g of stannicChloride At the Same temperatureagltatlon was 9 6 the amount of saidrepetitive photosensitive units (3) tlnlled for 3 hOuTS- After p ymacho" 0 being sufficient to impart photosensitive characteristicsmixture was treated in the manner of Example 1, to to said copolymer P ahght yellow polymer- 4. The photosensitive copolymer of claim 3 whereinThe Yleld was 3 and the reduced vlscoslty was said at least one chaincationically copolymerizable un- 0.17. saturated monomer (2) is selectedfromthe group consisting of alkylvinyl ethers, alkylisoalkenylvinylethers,

halostyrenes, isoalkenylvinyl ethers, olefins, isoalke- The P y thusObtained was formed a film nylstyrenes, vinyl carbazoles,vinyldioxolanes, butadiand exposed to light in the same manner as inExample enes and isoprenesl 1. Consequently, the film was insolubilized.

Treatment of photosensitive polymer-

1. A PHOTOSENSITIVE POLYMER CONSISTING OF A POLYMERIZED VINYL CHAIN OFREPETITIVE UNITS SELECTED FROM THE GROUP CONSISTING OF
 2. The polymer ofclaim 1, which is a copolymer and has at least two different repetitiveunits which differ in at least one of R and n.
 3. A photosensitivecopolymer having a chain formed by copolymerizing the CH2 CH group of atleast one monomer (1) of the formula
 4. The photosensitive copolymer ofclaim 3 wherein said at least one chain cationically copolymerizableunsaturaTed monomer (2) is selected from the group consisting ofalkylvinyl ethers, alkylisoalkenylvinyl ethers, halostyrenes,isoalkenylvinyl ethers, olefins, isoalkenylstyrenes, vinyl carbazoles,vinyldioxolanes, butadienes and isoprenes.